1. Field of the Invention
The present invention relates generally to the field of craft control, navigation, and collision prevention, and more particularly to a system and method of relaying craft position information derived by GPS via satellites to other participating craft to prevent collisions and inform the pilot or captain of possible procedures to follow.
2. Description of Related Art
The use of GPS positioning is well known in the art for all types of aircraft, watercraft, and land vehicles. Local systems exist where vehicles broadcast this information to other vehicles or craft in the vicinity (see for example U.S. Pat. No. 5,872,526). However, these systems do not provide location information that is available on a world-wide basis to participating users. Users must be within receiving distance of the cooperating aircraft or watercraft to receive reports.
U.S. Pat. No. 5,995,903 uses real world terrain depiction. GPS position is used to find the correct point in a terrain database.
There are many other prior art systems that use GPS for navigation and many proposals to improve the air traffic control system; however, none of these systems or proposals address the real problem of knowing where each craft in the system is and being able to report that to all other craft and then supplying information to the pilot or captain as to what to do in a certain situation.
What is badly needed is a system and method where position, course, speed, and altitude information (for ships, position, speed, and course) can be transmitted to satellites specifically designed to control such traffic on a world-wide or nation-wide basis. These satellites should communicate with each other so that all satellites can rebroadcast all available information. This way participating craft are always aware of the location of all other craft known about by the system. This system should inform the pilot or captain of collision hazards and provide information as to what to do in a given situation.
The POSTMAN/D (Positioning by Orbital Satellite Transmitting Marine and Aviation Navigational Data) system, that represents the present invention, is an integrated cockpit/bridge communications system that takes data known to each craft and provides it to other participating craft. By craft, I mean aircraft and watercraft of all types, missiles, and also optionally land vehicles.
The system of the present invention supplies a visual display of all craft in the area. Each participating craft computes its position in known ways via GPS/DGPS, or other possible ways such as Loran C, VOR, or any other means or method of determining absolute position. The preferred method is the use of GPS or DGPS known in the art. Each craft also possesses information on its own speed, heading, absolute altitude, and height above the ground for aircraft, as well as its attitude in terms of pitch, roll, and yaw. Generally three GPS satellites are needed for an a 3-dimensional fix.
Each participating craft can then uplink transmit this information via microwave link to at least one of a special constellation of POSTMAN/D satellites dedicated to this system. These satellites, located strategically around the world, communicate with each other via microwave or other communications means. In this manner, they share information concerning all participating craft.
Each participating craft also receives a downlink transmission of a broadcast nature from all POSTMAN/D satellites in its view. It is thus possible for any participating craft to have detailed, real time information of any other craft actively in the system.
Each craft is identified to the system by a unique serial number or hull number. This number can be programmed into the system at installation time and cannot be changed. Thus, whenever the on-board system is transmitting coordinate information, it is always using the correct, unchangeable hull or serial number of the craft. By coordinate information, I mean position, speed, heading, altitude, and height above the terrain. Thus, it is difficult, if not impossible, to fool the system into misidentification of any craft.
Thus, it is an object of the present invention to provide a system where each participating craft reports its position as determined from GPS, and its own parameters such as heading and speed to a system of repeaters which are satellites or other control points. The satellites are in communication with each other so information available at one satellite is available at every satellite. Each participating craft in the system receives information on location, heading, and speed of other craft. It can then display the status of other craft on a display; it can warn of impending collisions; and it can even be programmed to avoid collisions by supplying information to a craft""s autopilot.
Software in an on-board computer system correlates and classifies all data coming in from the POSTMAN/D satellites as to coordinates of other craft as well as coordinates for the that craft. Computations can be easily made to determine if there is any collision danger. A zone of protection can be computed around the craft based on speed and maneuverability. The system can provide the pilot or captain with instructions on what to do to avoid any potential collision or in any other situation. The system can optionally be programmed to take control of the craft to perform emergency maneuvers to avoid collision by sending data to the craft""s autopilot.
The basic on-board system can consist of a GPS/DGPS receiver, a microwave transceiver for communication with the POSTMAN/D satellites, an UHF transceiver for backup or local communication, a gyro stabilized antenna with a signal seeking device to lock on the best POSTMAN/D satellite, a display panel for the cockpit or bridge, and various interface equipment between the components. In addition, the basic system has inputs from the craft""s own instrument systems as to attitude roll and pitch (or heading in the case of a ship). This allows proper positioning of Icons on a display in the proper axis or real time flight attitude. The display software can supply simulated terrain or scenery similar to that of a flight simulator.
Once the system is activated, the stabilized antenna seeks and locks on the strongest available POSTMAN/D satellite. The system can be programmed to search for, and switch to, a stronger signal if one becomes available. The system begins immediately to transmit the craft""s ID number as well as absolute position in longitude and latitude (or other local coordinates), heading, speed, and altitude. The system also begins immediately to receive data from the POSTMAN/D system of satellites concerning other participating craft anywhere. Selection can be made by ranging to limit the incoming information to craft in a reasonable vicinity. Because information is available about all participating craft, the display can be centered or located on any craft in the system, not just the craft where the display is located. When the display is located on another craft, it shows all information relative to that craft.
Data to and from the POSTMAN/D satellites is generally in a data packet module format using the known techniques of digital data transmission. Each packet or module can contain error control bits and/or error correction capabilities. Any received packet or module that cannot be read for any reason can be rerequested. Data from the satellites is generally sent out in a broadcast mode to all craft in receiving range. Data to the satellite from any craft can be sent in a packet/collision communications mode known in the art, or by any other communications mode that allows multiple competing stations to communicate including time division, frequency division and code division multiplex.
The system can also be used to control or guide aircraft on the ground to guide them to proper destinations on an airport and to prevent ground collisions (either between aircraft or aircraft and vehicles). In this case, airport vehicles would also be participating craft in the system.
Alternate communication between local vehicles or in the case of bad weather could be by UHF radio. UHF could be used anytime that microwaves did not work. The POSTMAN/D satellites can optionally be used in conjunction with fixed ground stations set up along coastlines. These stations would act as repeaters communicating with the satellites via microwave and with craft by UHF if necessary.
The system can also be optionally programmed to provide instructions according to the rules of the road for vessels. This feature would be especially useful for inexperienced boaters faced with a possible collision hazard or if they wander into shallow or unsafe water.
The system for aircraft can, and should, have the feature of not being able to be turned off while the aircraft is in flight. This can be simply accomplished by providing input from switches sensing the landing gear down and with weight on the gear. This feature would allow operators anywhere to determine the location of any aircraft at all times even in situations where terrorists, for example, did not want the aircraft""s position to be known (for example by turning off the transponder). In addition, if there is such a change in course that an aircraft has totally deviated from its original flight plan, an emergency code can be sent to the satellite to declare an abnormal or emergency situation. Sometimes aircraft are asked to circle locations to xe2x80x9choldxe2x80x9d while in flight. The system could be programmed to recognize such a maneuver and not declare that an emergency. This could be done by recognizing that the aircraft is holding at a known navigation point. Also the aircraft could inform the system that it is holding.
The craft""s display will show all craft utilizing the system (in the selected range), and those not in the system but detected by any participating craft""s radar system. It can show an icon depicting the craft (model, color, logos, and similar identification information) as well as the craft""s serial number, the country of registration flag (to help controllers with choosing a secondary language for instructions if needed), the craft""s itinerary, the captain""s name, and the name of the owner or company. The information, other than the icon and serial number, need not be displayed on the display, but can be accessible by inquiry and can appear at the bottom of the screen, or elsewhere, in an area near the craft""s instruments being monitored by the POSTMAN/D system.
On the bottom of the screen, or elsewhere, a number of the craft""s instruments can be shown on a rotating basis, (unless they fall out of normal range reading and require immediate attention, at which time they will appear steady and oversize).
Thus it is an object of the present invention to control air traffic by self-reporting users worldwide.
It is an object of the present invention to provide positive identification of all traffic and its destination.
It is an object of the present invention to eliminate misinterpretation of commands caused by language barriers by providing secondary language reporting in any language.
It is an object of the present invention to optionally make use of a craft""s autopilot to navigate the craft safely to its destination.
It is an object of the present invention to also report craft not self-reporting when they are picked up by other participating craft.
It is an object of the present invention to allow an operator to visually watch traffic at any given point on earth limited only by software installed on his craft.
It is an object of the present invention to control air ground traffic much like automobile traffic.
It is an object of the present invention to provide collision deterrence by warning all concerned of impending danger long before anything happens.
It is an object of the present invention to pinpoint the exact location and details of all craft when an emergency situation develops.
It is an object of the present invention to provide expert guidance as to actions that should be taken by a pilot or captain to avoid a collision or other danger.
It is an object of the present invention to provide a deterrence against unlawful use of a craft by anyone.
It is an object of the present invention to be available to all craft large and small by secondary UHF communications.
It is an object of the present invention to provide field guidance of a tactical weapon such as a missile from anywhere in the world.
It is an object of the present invention to provide a means where aircraft pilots can see their position in relation to waypoints in route to a final destination.
It is an object of the present invention to allow ground controllers to track the position of aircraft at airport facilities using icons on a control display.